Basics of Heat Exchangers
What is the primary function of a shell and tube heat exchanger?
(To transfer heat between two fluids)
Which property determines the required heat transfer area?
Which property determines the required heat transfer area?
Range of Velocity for tube side?
1-3 m/s
What is a common cause of vibration damage in tubes?
(Flow-induced vibration or insufficient baffle support)
First step
Find Heat Duty
What are the two main components of a shell and tube heat exchanger?
(Shell and tubes)
What is the typical range of LMTD correction factor (F) for a 1-2 exchanger?
(0.75 to 0.95)
What is LMTD?
Log Mean Temperature Deferance
Why might you use multiple shell passes?
(To increase temperature difference and improve efficiency)
Roll of Baffles
Increase Shell side turbulance, support tubes
Which fluid generally flows through the tubes?
(The one with higher fouling tendency or corrosive nature)
What parameter is used to size the tube length and count?
(Overall heat transfer coefficient and required area)
Why is fouling factor added in design?
(To account for scaling and reduce performance over time)
What could cause tube side fouling?
(Contaminated or particulate-laden fluid)
%Excess area should be
10-20%
What is the purpose of baffles in the shell?
(To increase turbulence and improve heat transfer)
What maximum allowable pressure drop is commonly considered for the shell side?
80 Kpa
What is the effect of increasing tube pitch?
(Reduces pressure drop but also reduces heat transfer area density)
How can you reduce pressure drop without changing tube count?
(Increase tube diameter or reduce flow velocity)
Purpose of Fin in Heat Exchanger
Increase Contact Area
What type of flow arrangement provides better efficiency: counter-current or co-current?
(Counter-current)
How does increasing flow velocity affect heat transfer?
(Increases heat transfer coefficient but also pressure drop)
Which equation is used to calculate LMTD?
(LMTD = ΔT1 - ΔT2 / ln(ΔT1/ΔT2))
What operational change could help reduce thermal stress?
(Gradual temperature ramping or use of expansion joints)
What does TEMA stand for?
(Tubular Exchanger Manufacturers Association)